Method and apparatus for stripping cable

ABSTRACT

This disclosure relates to a method and apparatus for stripping the outer strand from a cable composed of a core and at least one wound strand by passing the cable through a rotating member with the core being drawn through a passage extending along the axis of rotation and the partially unravelled outer strand being drawn through another passage offset from the axis of rotation. The outer strand is unwound by being rotated about the core while simultaneously being drawn through the rotating member. A pneumatic shear timed in accordance with the rotation of the rotating member severs predetermined sections of the unwound outer strand.

United States Patent Bishop et al.

[54] METHOD AND APPARATUS FOR STRIPPING CABLE [75] Inventors: Dwight Bishop, l-lawesville, Ky.;

Ronald W. Baskin, Carrollton, Ga.

[73] Assignee: Southwire [22] Filed: May 27, 1971 [21] Appl. No.: 147,468

Company, Carrollton,

[ 1 Apr. 3, 1973 FOREIGN PATENTS OR APPLICATIONS 377,753 3/l921 Germany ..57/2.5

Primary Examiner-Werner H. Schroeder Attorney-Van C. Wilks and Herbert M. l-lanegan [57] ABSTRACT This disclosure relates to a method and apparatus for stripping the outer strand from a cable composed of a core and at least one wound strand by passing the cable through a rotating member-with the core being drawn through a passage extending along the axis of rotation and the partially unravelled outer strand being drawn through another passage offset from the axis of rotation. The outer strand is unwound by being rotated about the core while simultaneously being drawn through the rotating member. A pneumatic shear timed in accordance with the rotation of the rotating member severs predetermined sections of the unwound outer strand.

25 Claims, 3 Drawing Figures PATENTEDAFR 3 1973 SHEET 1 BF 2 NTORS BASKIN DWIGHT BISHOP 16 .6% A 57777 (7 INVE RONALD W.

ATTORNEYS PATENTEDAPR 3 I975 SHEET 2 BF 2 METHOD AND APPARATUS FOR STRIPPING CABLE This invention relates generally to the art of wire and cable manufacturing, and more particularly to a method and apparatus for stripping the outer strand from a cable composed of a core and at least one distinct layer of strands wound thereabout.

Wire cable is often manufactured by providing a center conductive core and winding distinct layers of wire thereabout. The outer layers are applied by tightly winding them about the core in a spiral fashion. The layered efiect is made more distinct and exaggerated by winding the strands of successive layers in opposite directions thereby distinguishing to which layer each strand of wire belongs.

In the past, damage to the outer layer of wire on the cable as a result of a mishap in the manufacturing or handling, or a deformity in the winding pattern itself, usually necessitated the scrapping of the entire cable. This was a result of the relatively intricate construction of alternately wound layers and the long and tedious process of unwinding and stripping that was required to remove the damaged outer layer of wire from the cable in order to save the undamaged core and inner layers. Because no satisfactory method existed for accomplishing this result that was not time consuming and expensive, the investment in man-hours and materials used in the original construction of the cable was lost.

It is, therefore, the primary object of this invention to provide a method and apparatus for rapidly and economically removing the outer strand from a cable composed of a core and at least one distinct layer of strands wound thereabout.

Another object of this invention is to provide apparatus for stripping a damaged outer layer of wire from a cable while simultaneously salvaging the remainder of the cable by taking-up the core and the other undamaged layers of wire.

A further object of this invention is to provide apparatus for removing the outer strand from a cable composed of a core and at least one distinct layer of strands wound thereabout comprising a member adapted to rotate about an axis, a first passage extending through the member along the axis of rotation, a second passage extending through the member along a path ofiset from the axis of rotation, means for drawing the cable through the member with the core extending through the first passage and the outer strand extending the drawing of the cable therethrough whereby the outer strand is unwound from the core.

Still another object of this invention is to provide ap paratus as described above including means timed in accordance with the rotation of the rotating member for severing sections of the unwound outer strand into lengths convenient for remelting.

Briefly, these objects are accomplished by providing a drum mounted for rotation about a horizontal axis and disposed between a supply spool on one side thereof containing the cable with the damaged outer layer, and a powered take-up spool on the other side thereof adapted to draw the core through a guide defining a passage along the axis of the drum and to draw the partially unravelled outer layer through a guide defining another passage through the drum along a path ofl set from the axis of the drum. The rotation of the drum simultaneous with the drawing of the cable therethrough causes the outer strand to be rotated about the core and thus unwound therefrom. Suitable means are provided for automatically severing predetermined lengths from the unwound outer strand while the core and the undamaged inner layers are wound on the take-up spool.

With the above and other objects in view that may hereinafter appear, the nature of the invention will be more clearly understood by reference to the several views illustrated in the accompanying drawings, the following detailed description, and the appended claimed subject matter.

IN THE DRAWINGS FIG. 1 is a perspective view of apparatus constructed in accordance with this invention, and illustrates a supply spool of cable from which the outer strand is desired to be removed, a take-up spool for the core, and a rotating drum disposed therebetween through which the cable is passed to unwind the outer strand from the core;

FIG. 2 is a partially schematic side elevation view of the rotating drum having portions thereof cut-away for clarity to show the outer strand-conducting guide and the rotary union assembly through which compressed gas is conducted to the shear for cutting the unwound strand;

FIG. 3 is a fragmentary end elevation view of the rotating member having portions cut-away for clarity to .show the interior of the rotary union assembly and the which is wound a supply of cable c. The cable c is composed of a core 13 and an outer layer of wire formed by a strand 14 wound thereabout. It should be understood that while the core 13 is disclosed herein as consisting of a single length of wire, it may in fact consist of several distinct layers of strands wound about a central conductor, the strand 14 merely comprising the outer layer of such a plurality of layers. In any event, the outer layer formed by the wound strand 14 is desired to be stripped from the core 13, be it a single conductor only, or a conductor surrounded by successive layers of wound strands.

The apparatus 10 further includes a take up spool 15 for the stripped core 13, and an unravelling mechanism 16 disposed between the supply spool 11 and the takeup spool 15. The take-up spool 15 is rotatably mounted in support blocks 17 by means of a shaft 18 having a pulley 19 suitably secured to its outer end. The spool 15 is powered by a motor 20 through a drive shaft 21 which transmits torque to the shaft 18 by means of a belt 22 which fits over the pulley 19 and another pulley 23 on the drive shaft 21. Rotation of the spool 15 serves to pull the cable 0 from the supply spool 1 1 and through the unravelling mechanism 16 in a manner to be hereinafter described.

The unravelling mechanism 16 includes a drum 24 having side flanges 25 and 26 suitably secured thereto. The drum 24 is rotatably mounted on a support frame 27 by means of disc-like rollers 28 disposed on both sides thereof as seen most clearly in FIG. 3. The rollers 28 are suitably journalled on shafts 29 mounted on the frame 27.

As seen most clearly in FIG. 2, a first guide tube 30 having an entrance bushing 31 and an exit bushing 32 extends through the drum 24 along the axis of rotation thereof. A second guide tube 33 having an entrance bushing 34 and an exit bushing 35 also extends through the drum 24 along a path offset from the axis of rotation thereof and preferably at an acute angle of approximately 30 to the first guide tube 30. Although the tubes 30 and 33 are shown in the drawings as being contained within a common plane, this is not a requirement and in fact the tubes 30 and 31 may define lines skew to one another.

The drum 24 is rotated by means of a motor 36 disposed beneath the frame 27 and having a drive shaft 37 extending therefrom. Drive cables or belts 38 frictionally encircle the drum 24 and pulleys 39 which are suitably secured to the. drive shaft 37.

In operation, the apparatus is first set-up by manually stripping back the end of the outer strand 14 from the core 13 sufficiently so that the core 13 may be threaded through the guide tube 30 and the outer strand 14 threaded through the guide tube 33. The core 13 is then suitably fastened to the take-up spool and the motor energized to begin pulling the cable c off the supply spool 11 and through the unravelling mechanism 16. Simultaneously, the motor 36 is ener gized to slowly rotate the drum 24 in the direction indicated by the arrow R as seen in FIG. 1. It should thus be readily apparent that as the cable 0 is drawn through the unravelling mechanism 16 the outer strand 14 is caused to be rotated about the core 13 and consequently unwound or stripped therefrom in a continuous manner. Because of the angle defined by the guide tube 33 relative to the axis of rotation of the drum 24, the stripped outer strand 14 exiting from the unravelling mechanism 16 through the bushing 35 describes the arc of an enlarging circle or frusto-conical surface of rotation.

As illustrated in the drawings, the strand 14 is wrapped around the cable 0 with a left-hand twist. Accordingly, the drum 24, as seen in FIG. 1, must be rotated counterclockwise to unwind the strand 14. In actual practice, the various layers'of strands'formed about the core 13 may be wrapped with either left-hand or right-hand twists, or various combinations thereof. It should be apparent, therefore, that the motor 36 may be of the reversible type, and that it could be operated to rotate the drum 24 either counterclockwise or clockwise to unwind both left-hand and right-hand twist layers, respectively.

Axial thrust imparted to the drum 24 by the cable 0 being drawn theretltrough is resisted by stabilizing rollers 40 which engage the flange 26. The rollers 40 are freely mounted for rotation on pins 41 carried by yokes 42 supported by upright angle bars 43 which are suitably mounted on the frame 27.

As the unwound outer strand l4 exits from the unravelling mechanism 16, predetermined lengths thereof are cut off by a pneumatic shear assembly 44 which is mounted on the flange 25 for rotation therewith by means of resilient mounts 45 as seen in FIG. 2. The resilient mounts 45 permit the shear assembly 44 to move slightly with the moving strand 14 during the cutting operation. The shear assembly 44 is of the guillotine type and includes a stationary blade 46 and a movable blade 47 suitably connected to a pneumatic piston (not shown). Compressed gas, typically air, is conducted from a source (not shown) through stationa ry tubing 48, into a rotary union assembly 49, and then through tubing 50 mounted for rotation with the drum 24 to a space above the piston which actuates the blade 47.

The rotary union assembly 49 includes a stationary portion 51 connected to the tubing 48, and a movable portion 52 suitably secured to the flange 25 and mounted for rotation about the stationary portion 51 on a plurality of ball bearings 53. A series of ports 54 in the stationary portion 51 communicates with an annular chamber 55 which permits the compressed air to pass from the interior of the rotary union assembly 49 to the tubing 50 and thence to the shear assembly 44. Suitable pneumatic seals (not shown) are provided between the stationary portion 51 and the movable portion 52 of the rotary union assembly 49.

In order to time the severing of the strand 14 in accordance with the rotation of the drum 24, there is provided a timing mechanism, generally indicated by the numeral 56, including a housing 57 mounted on the frame 27 and having a slot 58 formed in a side thereof through which extends a spring-biased arm 59. A camlike projection 60 formed on the flange 26 is adapted to engage and move the arm 59 once every revolution of the drum 24. Suitable relay means (not shown) in the timing mechanism 56, responsive to the movement of the arm 59, is adapted to transmit an electrical signal through a line 61 (illustrated schematically in FIG. 2) to a valve 62 disposed in the compressed gas supply tubing 48. A solenoid-type actuator (not shown) in the valve 62, responsive to the electrical signal transmitted through the line 61, is thus adapted to open the valve 62 thereby conducting compressed gas to the shear assembly 44 to sever the unwound strand 14. It should be obvious that if longer lengths of cut strands are desired, the timing mechanism 56 may include means for transmitting the electrical signal to the valve 62 only after a predetermined number of revolutions of the drum 24. In actual practice, the strand 14 is cut into wire lengths convenient for remelting into metal for re-use.

It should be further understood that other types of timing means are contemplated within the scope of this invention; including, for example, direct electrical contact between the rotating drum 24 and the relay means as by brush contacts on the flange 26. Similarly, the shear assembly 44 may be solenoid operated, rather than pneumatically actuated, by direct connection with the timing mechanism.

In view of the foregoing, it should be readily apparent that there is provided in accordance with this invention a method and apparatus for stripping a damaged outer layer of wire from a cable while simultaneously salvaging the remainder of the cable, which method and apparatus is both rapid and economical whereby substantial savings in time and money may be realized in contrast with the tedious and expensive hand-powered methods of the prior art.

Although only a preferred embodiment of the invention has been specifically disclosed and described herein, it should be understood that minor variations may be made without departing from the spirit of the invention.

We claim:

1. A method of stripping the outer strand from a cable composed of a core and at least one wound strand, comprising the steps of providing a rotating member, passing the core through the rotating member along the axis of rotation thereof, passing a partially unwound outer strand through the rotating member along a path offset from the axis of rotation thereof, rotating the outer strand about the core to unwind the outer strand from the core, and drawing the core through the rotating member to simultaneously draw the outer strand through the rotating member.

2. A method as defined in claim 1 wherein the outer strand is passed through the rotating member at an angle to the axis of rotation thereof.

3. A method as defined in claim 2 wherein the unwound strand describes an arc of an enlarging circle as it is drawn through the rotating member.

4. A method as defined in claim 1 including the step of taking up the stripped core.

5. A method asdefined in claim 4 wherein the taking up of the stripped core serves to draw the outer strand through the rotating member.

6. A method as defined in claim 1 including the step of severing sections of the unwound strand as it is drawn through the rotating member.

7. A method as defined in claim 6 wherein the severing of the unwound strand is timed in accordance with the rotation of the rotating member.

8. Apparatus for removing the outer strand from a cable composed of a core and at least one distinct layer of strands wound thereabout, comprising a member adapted to rotate about an axis, a first passage extending through said member along said axis, a second passage extending through said member along a path ofiset from said axis, means for drawing the cable through said member with the core extending through said first passage and the outer strand extending through said second passage, said drawing means functioning to simultaneously advance both the core and the outer strand through said member, and means for rotating said member about said axis simultaneously with the drawing of the cable therethrough whereby the outer strand is unwound from the core.

9. Apparatus as defined in claim 8 including means for severing sections of the outer strand as it 'is drawn through said rotating member.

10. Apparatus as defined in claim 9 wherein .said means for severing includes a pneumatically actuated shear carried by said rotating member.

11. Apparatus as defined in claim '10 including means for actuating said shear in accordance with the rotation of said rotating member.

12. Apparatus as defined in claim 8 wherein .said

second passage is disposed at an angle to said first passage.

13. Apparatus as defined in claim 8 wherein said passages define lines skew to one another.

14. Apparatus as defined in claim 8 including a supply spool disposed on one side of said member, a

take-up spool disposed on the other side of said member, and drive means for said take-up spool functioning to draw the cable through said meb er.

15. Apparatus as defined in claim 8 wherein said member includes a drum mounted for rotation about a horizontal axis, at least one side flange carried by said drum, and shear means resiliently mounted on said side flange for severing sections of the unwound outer strand.

1 6. Mechanism for u'ntwisting the outer layer of strands from a multi-strand cable comprising a cable supply reel, a core wire take-up spool, and a strand unraveling device situated therebetween, said strand unraveling device comprising a core wire confining and conducting guide having a first axis therethrough and a strand confining and conducting guide having a second axis therethrough angularly offset with respect to the axis of said core wire guide, said strand confining and conducting guide adapted to enclose an unwound strand along a substantial portion of its length, and means to rotate said core wire take-up spool to simultaneously advance both the core wire and the unwound strand through their respective guides.

17. The invention of claim 16 and further comprising means to orbit the unraveling guide about the core wire guide.

18. The invention of claim 16 in which said strand unraveling device comprises a drum having front and rear flanges residing in planes that are approximately perpendicular to the axis of the core wire guide, the said guides extending from the front flange to the rear flange of said drum.

19. The invention of claim 18 and further comprising power means to rotate said drum and orbit said unraveling guide about said core wire guide.

20. The invention of claim 16 in which the cable supply reel rotates about a cable supply reel axis, said cable supply reel axis being stationary during operation.

21. The invention of claim 16 in which the take-up spool rotates about a take-up spool axis, said take-up spool axis being stationary during operation.

22. The invention of claim 18 and further including a shear mounted on said drum, said shear functioning to sever various lengths of unraveled cable.

23. The invention of claim 18 in which said take-up spool is located free and clear of said drum.

24. The invention of claim 16 and further comprising the condition that the axes lie in different planes such that no single plane can contain all the axes.

25. The invention of claim 16 and further comprising the condition that the axes lie in the same plane. 

1. A method of stripping the outer strand from a cable composed of a core and at least one wound strand, comprising the steps of providing a rotating member, passing the core through the rotating member along the axis of rotation thereof, passing a partially unwound outer strand through the rotating member along a path offset from the axis of rotation thereof, rotating the outer strand about the core to unwind the outer strand from the core, and drawing the core through the rotating member to simultaneously draw the outer strand through the rotating member.
 2. A method as defined in claim 1 wherein the outer strand is passed through the rotating member at an angle to the axis of rotation thereof.
 3. A method as defined in claim 2 wherein the unwound strand describes an arc of an enlarging circle as it is drawn through the rotating member.
 4. A method as defined in claim 1 including the step of taking up the stripped core.
 5. A method as defined in claim 4 wherein the taking up of the stripped core serves to draw the outer strand through the rotating member.
 6. A method as defined in claim 1 including the step of severing sections of the unwound strand as it is drawn through the rOtating member.
 7. A method as defined in claim 6 wherein the severing of the unwound strand is timed in accordance with the rotation of the rotating member.
 8. Apparatus for removing the outer strand from a cable composed of a core and at least one distinct layer of strands wound thereabout, comprising a member adapted to rotate about an axis, a first passage extending through said member along said axis, a second passage extending through said member along a path offset from said axis, means for drawing the cable through said member with the core extending through said first passage and the outer strand extending through said second passage, said drawing means functioning to simultaneously advance both the core and the outer strand through said member, and means for rotating said member about said axis simultaneously with the drawing of the cable therethrough whereby the outer strand is unwound from the core.
 9. Apparatus as defined in claim 8 including means for severing sections of the outer strand as it is drawn through said rotating member.
 10. Apparatus as defined in claim 9 wherein said means for severing includes a pneumatically actuated shear carried by said rotating member.
 11. Apparatus as defined in claim 10 including means for actuating said shear in accordance with the rotation of said rotating member.
 12. Apparatus as defined in claim 8 wherein said second passage is disposed at an angle to said first passage.
 13. Apparatus as defined in claim 8 wherein said passages define lines skew to one another.
 14. Apparatus as defined in claim 8 including a supply spool disposed on one side of said member, a take-up spool disposed on the other side of said member, and drive means for said take-up spool functioning to draw the cable through said member.
 15. Apparatus as defined in claim 8 wherein said member includes a drum mounted for rotation about a horizontal axis, at least one side flange carried by said drum, and shear means resiliently mounted on said side flange for severing sections of the unwound outer strand.
 16. Mechanism for untwisting the outer layer of strands from a multi-strand cable comprising a cable supply reel, a core wire take-up spool, and a strand unraveling device situated therebetween, said strand unraveling device comprising a core wire confining and conducting guide having a first axis therethrough and a strand confining and conducting guide having a second axis therethrough angularly offset with respect to the axis of said core wire guide, said strand confining and conducting guide adapted to enclose an unwound strand along a substantial portion of its length, and means to rotate said core wire take-up spool to simultaneously advance both the core wire and the unwound strand through their respective guides.
 17. The invention of claim 16 and further comprising means to orbit the unraveling guide about the core wire guide.
 18. The invention of claim 16 in which said strand unraveling device comprises a drum having front and rear flanges residing in planes that are approximately perpendicular to the axis of the core wire guide, the said guides extending from the front flange to the rear flange of said drum.
 19. The invention of claim 18 and further comprising power means to rotate said drum and orbit said unraveling guide about said core wire guide.
 20. The invention of claim 16 in which the cable supply reel rotates about a cable supply reel axis, said cable supply reel axis being stationary during operation.
 21. The invention of claim 16 in which the take-up spool rotates about a take-up spool axis, said take-up spool axis being stationary during operation.
 22. The invention of claim 18 and further including a shear mounted on said drum, said shear functioning to sever various lengths of unraveled cable.
 23. The invention of claim 18 in which said take-up spool is located free and clear of said drum.
 24. The invention of claim 16 and further comprising the condition that the axes lie in dIfferent planes such that no single plane can contain all the axes.
 25. The invention of claim 16 and further comprising the condition that the axes lie in the same plane. 